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Trypanosomiasis

Overview

(Human) African trypanosomiasis (HAT) is caused by Trypanosoma brucei rhodesiense or gambiense following the bite of an infected Tetse fly. This disease is restricted to Africa. The Department of Clinical Parasitology should be IMMEDIATELY notified about any suspected cases of African trypanosomiasis sent for diagnosis to ensure that the samples arrive correctly and are rapidly progressed as disease progression to Stage 2 (CNS involvement) can be rapid.

American trypanosomiasis (Chagas disease) is caused by Trypanosoma cruzi. Once confined entirely to the Americas, it has now spread to other continents. Testing is most generally performed following suitable travel or clinical history or to screen potential organ donations.

Please include relevant travel and clinical history with all requests for Trypanosomiasis so that the correct testing may be performed.

 

African Trypanosomiasis

Diagnosis of (Human) African Trypanosomiasis by microscopy

  • Sample type: A minimum of 2ml of EDTA anti-coagulated blood and/ or as much CSF as you can spare.

Trypanosomes quickly disintegrate upon removal from the body, therefore, it is vital that specimens for microscopy are examined rapidly. EDTA whole blood must be examined within 24 hours and CSF within 20 minutes of taking the sample.

If there is the possibility of a delay in the receipt of EDTA whole blood for microscopy, films should be made locally for examination.

Diagnosis is made by examining stained blood films or CSF in cases with neurological involvement.

Diagnosis of (Human) African Trypanosomiasis by serology

  • Sample type: A minimum of 0.5ml of serum or as much CSF as you are able to spare where neurological involvement is suspected.

Sera are screened by IFAT for Trypanosoma brucei.

Please give the relevant travel history so that the appropriate species can be tested for Trypanosoma brucei rhodesiense and gambiense, which have different geographical locations in Africa and are tested by different IFAT slides.

 

American Trypanosomiasis (chagas disease)

Diagnosis of Chagas disease by microscopy

  • Sample type: A minimum of 2ml of EDTA anti-coagulated blood

Microscopy on blood films can be performed for diagnosis of T. cruzi following consultation with the Clinical Parasitologist. Bloods should be taken for examination within two months of the acute phase of infectionor reactivation in cases of immunosuppression.

Diagnosis of Chagas disease by PCR

Sample type: Two tubes of 5ml of EDTA anti-coagulated blood

This test is referred to the London School of Hygiene and Tropical Medicine. Please contact the Clinical Lead for Parasitology before requesting this test.

Diagnosis of Chagas disease by serology

Sample type: A minimum of 0.5ml of serum is required for serological analysis.

Screening and serodiagnosis of T. cruzi is performed by ELISA plus IFAT.